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Copper‐Free Monomeric and Dendritic Palladium Catalysts for the Sonogashira Reaction: Substituent Effects, Synthetic Applications, and the Recovery and Re‐Use of the Catalysts
Author(s) -
Heuzé Karine,
Méry Denise,
Gauss Dominique,
Blais JeanClaude,
Astruc Didier
Publication year - 2004
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200400150
Subject(s) - sonogashira coupling , catalysis , dendrimer , chemistry , palladium , phosphine , substituent , copper , monomer , coupling reaction , combinatorial chemistry , polymer chemistry , organic chemistry , polymer
A series of bis( tert ‐butylphosphine)‐ and bis(cyclohexylphosphine)‐functionalized Pd II monomers and polyamino (DAB) dendritic catalysts were synthesized and investigated for Sonogashira carbon–carbon coupling reactions in a copper‐free procedure. The influence of phosphine substituents ( t Bu versus Cy) on the reaction kinetics was investigated by a GPC technique to monitor the reactions. The dendritic catalysts containing the cyclohexylphosphine ligands could be recovered and reused without loss of efficiency until the fifth cycle. The dendritic Pd II catalysts show a negative dendritic effect, that is, the catalyst efficiency decreases as the dendrimer generation increases.